1. Field of the Invention
The present invention relates to an illuminated logo unit, and particularly to an illuminated logo unit having uniform illumination in each of discrete illumination areas thereof.
2. Prior Art
A conventional logo unit, such as a registration mark on a billboard or an insignia on a vehicle, cannot illuminate itself. If the image of the logo unit is to be clearly seen at night, it must be illuminated by an external source. However, external illumination has various inherent limitations, including the angle of illumination, the brightness of the source, and the reflective ratio of the logo unit. These limitations frequently result in the logo unit being unevenly illuminated. Furthermore, the brightness and overall display of the logo unit may be unsatisfactory.
Generally, to solve the above-described problems, an active light source is arranged at the back of the logo unit. A logo unit having an active light source arranged at the back thereof is known as an illuminated logo unit.
A conventional illuminated logo unit 100 as disclosed in U.S. Pat. No. 6,174,075 is represented in FIG. 7. The unit 100 has a top surface 110, and a circumferential lip 132 which may be used to secure the unit 100 to a garment or another article such as a hat. The top surface 110 includes one or more graphic elements, which form a predetermined design. The top surface 110 may be separated from the lip 132 by a cylindrical sidewall 131. The unit 100 is formed with a central cavity 135, which spans to a bottom surface (not labeled) of the unit 100. The cavity 135 is structured to receive a light source system 133, which transmits light beams to pass through the top surface 110. The light source system 133 has a point light source 137, and batteries 138 providing power to the point light source 137.
Because the point light source 137 is arranged corresponding to a center of the top surface 110, the distribution of light energy over the whole top surface 110 from the point light source 137 is uneven. For example, a central circular area on the top surface 110 receives much more light energy from the point light source 137 than other portions of the top surface 110. Accordingly, a brightness of the top surface 110 is not uniform. The result is that the entire top surface 110 cannot be clearly seen at night.
A new illuminated logo unit that overcomes the above-mentioned disadvantages is desired.